Bone plates for osteosynthesis or arthrodesis are often fixed to bone substantially parallel to a longitudinal bone axis using screws or other fixation elements. Such bone plates are firmly fixed to the bone to prevent bone parts or fragments from moving relative to each other. When fixing a bone plate to bone particular care is to be taken in cases of peri-implant fractures, including periprosthetic fractures, for example. Periprosthetic fractures are fractures around a joint or other prosthesis, whereas peri-implant fractures more generally denote fractures around any type of implant.
When a periprosthetic fracture is to be treated, in which a prosthetic device (e.g., with a ball joint and a stem) partially extends into a medullary canal of the fractured bone, the surgeon generally has to keep in mind that the fixation elements repairing the fracture must not intrude into the medullary canal where the prosthetic device has been inserted. In such cases, an attachment device can be used which is adapted to accommodate the bone plate.
Each of U.S. Pat. No. 4,973,332 and U.S. Patent Application Publication No. 2010/0262194 discloses periprosthetic repair systems comprising a long bone plate and an attachment device. The long bone plates shown are configured to hold fracture parts of the long bone together to promote healing of the fractured bone, for example. The attachment devices are adapted to be arranged on the long bone plates. Specifically, the attachment devices form a partial overlay which fits over and accommodates the long bone plate.
These attachment devices also include finger-like structures or wings that are inclined with respect to a central portion of the attachment devices and are adapted to extend around at least a portion of the femur. For anchoring the attachment devices in the femur, each wing has a hole for receiving a screw which is screwed into the femur.
When attaching the long bone plate using the attachment device, it is desired that this attachment offers a high stability so that the bone fragments of the fractured long bone can effectively consolidate. However, when a prosthetic device extends along the length of the bone, the screws for anchoring the attachment device are preferably anchored in the outer hard layer of the bone. That is, they preferably should not penetrate into the medullary canal of the bone.
The attachment device of the repair system disclosed in U.S. Patent Application Publication No. 2010/0262194 further includes receiving holes that are aligned to receive fixation elements that do not pass through a longitudinal axis of the medullary canal. However, aligning the receiving holes requires fixing the attachment device to the long bone plate with a fixation element or, in the alternative, clumsily sliding the attachment device over the plate prior to fixation of the attachment device to the plate to an appropriate position of the receiving holes and in which the long bone plate and the attachment device are aligned for attachment to each other.
Thus, there exists a need for a way in which to align an attachment portion for receiving a fixation element to be used for the repair of peri-implant fractures without the need for a separate fixation element.